Same thing last week as well, I checked the site as soon as the email arrived and all loans had gone.
I hope things start improving as its getting a bit frustrating now.
There is more to it than that, I actually got the email twice !
First time it is timed at 17.52 on 4th April. I would have been in the car on the way home so could not have reacted anyway. Picked up the email about 6.20pm and the three loans mentioned were gone, there was a different loan and i took a holding.
Then at 2pm today I got the identical email again, checked and there were no loans, all fulfilled Thursday as you say.